Sandra Bullock and George Clooney's upcoming flick 'Gravity' is adding major buzz to the Toronto Film Festival. / Andreas Rentz, Getty Images

by Donna Freydkin and Andrea Mandell, USA TODAY

by Donna Freydkin and Andrea Mandell, USA TODAY

Perhaps more than any other film festival, Toronto's cinematic conclave is a blend of the casual, the pedigreed and the outright glitzy. True, stars abound in Canada's largest city, but the prevailing vibe is one of friendliness, intimacy and approachability. And it's the place where Oscar buzz really started in earnest for films such as 1999's American Beauty and 2008's Slumdog Millionaire, and actors like Marisa Tomei and Mickey Rourke in 2008's The Wrestler - a drama that didn't even have distribution until Toronto.

"My career started at film festivals. That's how my movies were shown to the public. Where else can you walk into a lobby and 'Oh, my God, there's Michael Fassbender'?" marvels Jessica Chastain, the Oscar nominee whose film The Disappearance of Eleanor Rigby is for sale this year.

And for Josh Brolin, who headlines Jason Reitman's drama Labor Day, the festival represents a professional turning point. "Toronto is Jason's home. It's very personal to him. As for me, No Country for Old Men started in Toronto. It's a great memory for me," he says of the film, which went on to win best picture. "And with this movie, I'm excited that the audience gets to experience it. I know this is going to have an emotional impact."

Even Thor is putting down his hammer for the event. Chris Hemsworth, whose bulk and dry wit powered up the Avengers franchise, is leaving Marvel's universe for Ron Howard's 1970s Formula One tale, Rush. "To be absolutely honest, I haven't been to any film festivals," he says. "This is my first one. I've always been hugely excited about the idea of traveling somewhere with a film, especially something I'm this proud of, to be a part of something people are responding to so well. I can't wait."

Perhaps no genre jump is as notable as director Bill Condon's, who shifts from Twihards to hackers after helming the last two chapters of The Twilight Saga. This week, he's premiering his WikiLeaks thriller, The Fifth Estate. "From Comic-Con to Toronto, right?" says the director, who has previously brought Dreamgirls and Kinsey to TIFF. "It's just a perfect place to premiere."

Here are six reasons you should be paying attention to the Toronto International Film Festival.

Blue-chip releases and flashy would-be blockbusters hit the court of public opinion.

The kidnapping thriller Prisoners, the cosmic nail-biter Gravity, the car-racing saga Rush,The Fifth Estate's no-holds-barred dissection of Julian Assange. Every festival, no matter how pedigreed, showcases big stunners hoping to wow audiences. This year, one of the most-talked-about is Gravity, featuring Sandra Bullock and George Clooney as scientists lost in space. "The narrative was stripped into a very visceral journey with only two characters in a very hostile environment without ever stopping the action or the suspense. The main theme of the film is the possibility of rebirth out of adversity," says writer/director Alfonso Cuaron. And speaking of strength, he's in awe of Bullock. "She's so meticulous about every single detail. She has amazing discipline. She started working out like crazy three months before shooting. She started rehearsing with the stunts and puppeteers because she was assisted by puppeteers. She's tireless," he says.

Audiences are also keeping an eye on Rush, Ron Howard's new take on the legendary 1970s rivalry between wild-card, sex-addicted driver James Hunt (Hemsworth) and the disciplined, calculating Niki Lauda (Daniel Bruhl). Hemsworth shed 30 pounds to squeeze his muscled frame into Hunt's bottle-size car - and amped up the charm. "Back then, anything went, and they really did the rock-star lifestyle" thanks to a looming threat of death, says Hemsworth. He laughs at the idea of showing up in Toronto in ripped jeans and bare feet, a stunt favored by the tradition-eschewing Hunt. "I tend to have a slightly different approach to how he did things." How did he learn to drive the lightweight race cars? " 'Drive it like you stole it' was the advice I got from one of the mechanics," he says.

Then there's the buzzy The Fifth Estate, which will open the festival with a gala screening Thursday. Its portrayal of Assange (played by Benedict Cumberbatch) is sure to be divisive; Assange himself refused to consult on or condone the film. "I've been wanting to make a political film for a long time," says Condon, whose WikiLeaks movie examines the platinum-haired leader's ambitions."I've heard people say when they watched it they changed their mind about him every 10 minutes," says Condon - and that's the point. A tip on making a movie about hackers? "There was never a script that was on a computer that was online," says the director.

Actors turned directors showcase their skills. Jason Bateman, Mike Myers and Keanu Reeves all go behind the camera. The ever-private Myers will reveal his documentary Supermensch: The Legend of Shep Gordon, about the legendary music producer, Keanu Reeves will pop up to debut his Man of Tai Chi (he also stars).

Industry icons will unveil new passion projects. Alfonso Cuaron has Gravity, Paul Haggis returns to the scene (and Belgium, where he's been editing) with romantic drama Third Person and Spike Jonze is spotlighting parts of his November release, Her, this Sunday. Cuaron has fond memories of Toronto â?? it's where he showed his breakthrough film, 2001's Y Tu Mama Tambien. "I feel very grateful. I love that festival. My first time there, I was stranded when it was Sept. 11. It was a dark cloud but on the plus side, we were stranded in a place where they were showing an amazing film program," he says.

It's A-list-palooza. Toronto abounds with bold-faced names, many of them Oscar winners or nominees. But everyone mostly brushes elbows and geeks out at the small dinners and parties that abound at venues like the Ritz-Carlton, Patria and the Soho House. "It's like being back in college, in the dorm at Julliard. A film festival is where you can look around, and I'm constantly meeting someone I really admire," says Chastain, who burst into starstruck tears upon meeting Gary Oldman at one point. Famous exes Brad Pitt and Jennifer Aniston will both be in attendance, but they'll miss each other by miles, as Pitt's 12 Years a Slave debuts Friday and Aniston's indie drama Life of Crime closes the festival on the 15th. As for Winslet, who's pregnant with her third child, expect the actress to be as congenial and professional as ever while promoting Labor Day. "Kate is one of the boys. I got along with her very well. She has a great, very on-the-edge humor that I understand. She gets it. She's there to do the work and have some fun," says Brolin.

The festival kick starts this year's Oscar machine. After summer's incessant explosions and superhero suits, Toronto provides a welcome return to more thoughtful film fare. 12 Years a Slavestunned audiences at Telluride, and is expected to be a serious contender this awards season, particularly for the work of director Steve McQueen and lead Chiwetel Ejiofor. The film is based on the biography of Solomon Northup, a free black man kidnapped in 1841 and sold into slavery in the South. Ejiofor says depicting Solomon's newly violent world required mentally going down the rabbit hole, "sort of Alice in Wonderland that you were suddenly transported to this other universe," one dominated by a mercurial plantation owner (Michael Fassbender). "It's subject matter that has a tough time getting made," says Pitt, who produced and cameos. "It's an incredibly important story. It's a masterwork for a director, and there are some performances in there that are as good as I've ever seen."

Dallas Buyers Club, starring an emaciated Matthew McConaughey as an unlikely AIDS activist, is having its world premiere at Toronto on Saturday. And Julia Roberts and Meryl Streep team up in John Wells' August: Osage County, the film adaptation of the Pulitzer Prize-winning play about a seriously troubled family. Idris Elba, too, is ginning up buzz for his portrayal of Nelson Mandela, the same week the ailing anti-apartheid icon has been discharged from the hospital. Elba calls the Toronto debut for his biopic Mandela: Long Walk to Freedom "judgment day." "It was important that people understood parts of his life that are not so well known, like his young life," says Elba. To play the leader, Elba spend a night in a cell on the infamous Robben Island, where Mandela was held. "It was supremely lonely, man," he says. "You felt completely helpless. In that experience, in those 12 hours of my life, I realized what 19 years must have been like in one cell. It completely gave me a different perspective on what it is I'm playing here."

It's a chance to catch up with entertainment's most tireless workhorses. Cumberbatch, Daniel Radcliffe, Dane DeHaan all refuse to stop at just one movie â?? Cumberbatch's films include the blue-chip releases 12 Years a Slave, August: Osage County and The Fifth Estate. "It's interesting to catch somebody right at that moment when obviously Sherlock has brought such attention and now this is sort of the next step into international stardom," says Condon. "It will be interesting to see how this (level of fame) sort of sits on him." James Franco's got two films to debut: Child of God, which he directs, and Palo Alto, based on the novel he wrote (he stars). "There's a handful of us with a bunch of films. Dan has three movies. He's pretty busy too," says DeHaan, who's co-starring in Kill Your Darlings with the Harry Potter star. Audiences will also see much of Bruhl, previously known for Inglourious Basterds, breaks out in a big way with two films: opposite Hemsworth in Rush and Cumberbatch in The Fifth Estate.